Pressure regulators of this kind are known, for example, from DE 44 19 168 A1 and are used to regulate the pressure in a medium-conducting line, by which an application device is fed. For example, such pressure regulators are employed in paint lines of a painting installation. Other fields of application are the material supply for applying an underbody coating or for seam sealing in vehicle bodies. The latter applications come under the term of a so-called thick-matter supply, since the media applied there are generally very viscous.
The formation and shape of the application jet depends inter alia substantially on the viscosity of the medium to be applied and it is the aim to ensure a uniform volume flow to the application device with the aid of the pressure regulator.
For this purpose, a pressure sensor and/or a volume flow sensor are in most cases present in the medium-conducting line. The pressure regulator is then activated in dependence on the output signals of the sensor(s). When the through-flow path of the pressure regulator is open, there is formed between the closing element and the valve seat an annular gap, the passage cross-section of which depends on the position of the closing element relative to the valve seat. Via this and via optionally present flow spaces with variable volume, the through-flow of the application medium can be regulated.
In the course of operation, there arise wear phenomena, especially on the closing element and on the valve seat, in a form that results in a wear of the closing element and of the valve seat to a greater or lesser degree. This wear occurs especially when the conveyed application medium is viscous, abrasive or aggressive or has more than one of these properties.
The wear may result in the cooperating components of closing element and valve seat no longer being perfectly matched to one another. As a result, the operational reliability of the pressure regulator is no longer guaranteed. Hitherto, such wear has come to light only through a fault which has already occurred and which leads to a shutdown of operation during operation, since the pressure regulator affected has to be exchanged immediately after the occurrence of the fault during the operating time.